Leafy Green and Cruciferous Vegetables Good for Gray Matter and Older Brains

 

The study enrolled 122 healthy participants aged 65 to 75 who solved problems and answered questions on a standard test of crystallized intelligence. Researchers also collected blood samples to determine blood serum levels of lutein and imaged participants’ brains using MRI to measure the volume of different brain structures.

The team focused on parts of the temporal cortex, a brain region that other studies suggest plays a role in the preservation of crystallized intelligence.

The researchers found that participants with higher blood serum levels of lutein tended to do better on tests of crystallized intelligence. Serum lutein levels reflect only recent dietary intakes, Zamroziewicz said, but are associated with brain concentrations of lutein in older adults, which reflect long-term dietary intake.

Those with higher serum lutein levels also tended to have thicker gray matter in the parahippocampal cortex, a brain region that, like crystallized intelligence, is preserved in healthy aging, the researchers report.

“Our analyses revealed that gray-matter volume of the parahippocampal cortex on the right side of the brain accounts for the relationship between lutein and crystallized intelligence,” Barbey said. “This offers the first clue as to which brain regions specifically play a role in the preservation of crystallized intelligence, and how factors such as diet may contribute to that relationship.”

“Our findings do not demonstrate causality,” Zamroziewicz said. “We did find that lutein is linked to crystallized intelligence through the parahippocampal cortex.”

“We can only hypothesize at this point how lutein in the diet affects brain structure,” Barbey said. “It may be that it plays an anti-inflammatory role or aids in cell-to-cell signaling. But our finding adds to the evidence suggesting that particular nutrients slow age-related declines in cognition by influencing specific features of brain aging.”

Barbey is an affiliate of the Carl R. Woese Institute for Genomic Biology and the Beckman Institute for Advanced Science and Technology at the U. of I.

The research team also included Beckman Institute postdoctoral researchers Erick Paul and Chris Zwilling; psychology professor Neal Cohen, also at Beckman; Elizabeth Johnson, of Tufts University; and Matthew Kuchan, of Abbott Nutrition.

Abbott Nutrition supported this work through the Center for Nutrition, Learning and Memory at the U. of I. in Urbana-Champaign.

Contacts and sources:

Diana Yates

University of Illinois Urbana-Champaign

Citation:  “Parahippocampal Cortex Mediates the Relationship Between Lutein and Crystallized Intelligence in Healthy, Older Adults” is available online